In recent years, a quantitative analysis method using a liquid chromatograph mass spectrometer has been used for chemical components and metabolite in biological samples and residues in environmental samples, and the like in many cases. A mass spectrometer is used as a high-sensitivity detector for liquid chromatography. Examples of the mass spectrometer include a quadrupole mass spectrometer, an ion trapping mass spectrometer, and a time-of-flight mass spectrometer, and these mass spectrometers are used depending on purposes of measurement. For quantitative analysis, the quadrupole mass spectrometer is used in many cases.
The quadrupole mass spectrometer can measure a mass number by two schemes, namely scanning measurement and selected ion monitoring (SIM). In the scanning measurement, scanning is performed within a predetermined mass number range, and spectra of ions included in the set mass number range are detected. This scanning method is used for qualitative analysis of unknown samples, for example. In the SIM measurement, chromatograms of ions with specific mass numbers designated in advance are selectively detected. This method is used in a case where analysis target components are known and quantitative analysis of the components is performed with high sensitivity.
In the related art, it is necessary for a technician to scan and measure a target sample in advance, to check mass spectra of detected components, and to determine mass numbers as targets of the SIM measurement in a case of determining the mass numbers for the SIM measurement. Thereafter, the mass numbers selected by the technician are used to display the mass chromatograms, and a characteristic mass number is determined for each target peak of the SIM measurement.
However, there is no means for automatically selecting an optimal mass number (maximum intensity or the like) for each peak in the liquid chromatograph mass spectrometer in the related art. Therefore, the spectrometer selects the mass number for each peak based on the determination by the technician, then extracts a mass chromatogram corresponding to the selected mass number, and further determines elution time (start and end time of the chromatogram) of the extracted mass chromatogram. In a case where the number of components as targets of measurement is large, it is necessary to set time for performing optimal SIM measurement in consideration of overlapping of the respective component peaks and the like, and there is a problem that it takes long time for the technician to determine and execute SIM measurement conditions.
According to Patent Literature 1, a mass number corresponding to each targeted component of quantitative analysis is determined by scanning data of the component as quantitative analysis in advance and is regarded as a mass number at the time of the SIM measurement. Patent Literature 1 is characterized in that mass spectrometry of the mass number corresponding to each targeted component is performed for predetermined time before and after a peak timing regardless of differences in the targeted components.